Hot Town in the Summertime

Denver has a particularly temperate climate but it does get hot and even humid there. Last summer there were several stifling days while I worked tearing out the walls. So I was planning to find a cooling solution for this summer.

I thought about installing an ERV as it is a device we want to add anyway. LEED recommends using an Energy Recovery Ventilator (or Heat Recovery Ventilator that is essentially the same technology but does not exchange humidity while recovering heat from the exhausted air) to bring adequate amounts of outside air into a tightly sealed house. These devices do not control temperature, they only introduce tempered air (tempered by the existing air in the home that is being exhausted.) So another source of cooling would be required. I’ll continue to plan for an ERV, but at this stage of construction, we are not ready to add one.

For this summer the best solution seems to be a used evaporative (swamp) cooler. My son-in-law is quite happy with the low energy use and cooling capacity of the cooler that is installed on the roof of his house. An evaporative cooler does take some attention to run effectively.

Master Cool Evap Cooler

Master Cool Evaporative Cooler

The cooler I found on craigslist is 5500 cfm, so enough to cool at least 1800 square ft. It was made by Adobe Air around 2006 if the serial numbers included the year of manufacture.  Arizona used to be the capital of swamp coolers and there are still some homes cooled only by one of these devices which use a pump, fan and running water but no refrigerant. Evaporative coolers use a relatively low amount of energy to cool but are limited by the difference between dry bulb (the temperature measured with a dry thermometer) and wet bulb (the temperature of yes, a wet thermometer in the hot air.) In areas of low humidity, just wetting the air that is blown into the house will cool it up to 30 degrees or so, and usually below comfort levels. However, if the air already holds water because it is humid, then the wet bulb temperature is not significantly lower than the dry and the devices don’t provide much cooling.

Adobe Air was located in Phoenix and was the largest manufacturer of these devices but unfortunately they went out of business and sold their brand MasterCool to Champion, a company that still makes coolers but does not utilize some of the technologies that Adobe Air pioneered. When they were at their peak, they made the most efficient and reliable coolers on the market. It is difficult to find a modern evaportive cooler that used the technologies they employed. There is a company in Colorado, called Coolerado, that makes only a commercial cooler at this time that uses more advanced technologies. And the Speakman company, famous for its showerheads, sold their OAsys brand to a company in Nevada who still manufactures this more sophisticated design that was invented at UC Davis, but these coolers are expensive. Way too expensive to be a temporary solution, cooling for construction work this summer.

The windows in the house are either awning or casement and are not particularly conducive to a window air cooler, but Dave suggested the front door instead. We intend to replace the front door anyway so I will build an insulated panel to fit the space for the old front door and put the cooler in the covered area in front of that door. I will run water to it from an outdoor spigot through some of the leftover pex pipe and plug it into an outlet inside. Hopefully I will learn from Rob how best to run it to keep the house cool on hot summer days.

Update: The install went well, just bought the poly line for about $5.00. Attached to the faucet adapter that came with the cooler, but it seems to have a steady drip at the connection. Oiled the motor and had to push the blower a bit to get it started but it is working fine. I had to move the location to one of the awning windows because the entry area blocked the free flow of air to the cooler. The awning window was attached to the opener with screws so it was not difficult to remove.

Of course after the first day it started to rain so it was not as effective as on dry hot days. I used old pipe insulation around the window trim to get it sealed and stuffed the surrounding area with pipe insulation and XPS. It appears to have sealed reasonably well. Had to make screens to keep the windows open while the cooler is operating too. The cooler blows air into the house and unless inside air can escape at about the same rate, the cooler can’t replace the warmer inside air with cooled air. (An air conditioner removes the warm air as it operates.) I also put a screen behind the inside grille of the cooler because I noticed several mosquitoes in the house. Don’t think they had time to breed in the water, but the water might attract them. The screening should shut out any bugs crawling or flying through the unit.

I kept the cooler running 24 hours a day unlike my kids who turn theirs off during the day and let the house stay shut up and cool until the hot afternoon temperatures overtake it. I found that under construction, the house was losing the overnight cool by early afternoon hours and constant cooler air movement made it more comfortable to work in the house. It is a successful temporary solution for the summertime.

Evaporative Cooler Install

Evaporative Cooler Install

Evaporative Cooler in Window

Evaporative Cooler in Awning Window Opening



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